Internal-combustion-engine piston



April 22, 1930. H, A, sbu s ET-AL 1,755,710

INTERNAL COMBUSTION ENGINE PISTON Filed June 50, 1927 I I /5' INVENTO\RZ3 Patented Apr. '22, 1930 UNITED STATES PATENT OFFICE mom) A. SOULISAnn WTLBUR '1'. soULis, on EAS'ION, PENNSYLVANIAlNTERNALCOMBUSTION-ENGINE PISTON Application filed June 80,

The invention is an improvement in pistons for internal combustionengines and means tor constructlng the same whereby the efliciency ofinternal combustion engines in 1 5 which our invention is embodied willbe materially increased.

As is well known, pistons constructed of all iron are strong and havegood wearing qualities. However, cast iron pistons are heavy and theirthermal conductivity is low; therefore the compression ratio must beheld down and the speed of the engine limited. As the tendency in modernengine design is to raise the compression ratio and increase the enginespeed, the iron piston hinders the advancement of engine design. Thealuminum piston has high thermal conductivity and is light in'weight,but due to the inherently poor wearing qualities of aluminum the pistonis short lived. The aluminum piston also has a high ratio of expansionwhich does not permit the piston to be fitted in the cylinder to limitsclose enough to prevent piston slap and oil pumping and loss ofcompression. It is seen that a piston to have ideal wearing and thermalproperties and to be light in weight must be constructed of more thanone metal. Therefore a bi-metallic piston of a substantial constructionwill be light in weight and have high thermal conductivity. It willtherefore have all of the advantages and none of the disadvantages of apiston of cast iron or of aluminum.

35 An object of our invention is to so construct a piston of two unlikemetals that they will be permanently united in a, manner to securelylock the two metals together so as to keep the uniting joint together atall times so as to function like a piston constructed of a singlecasting.

A further object of our invention is to provide a piston for use in aninternal combustion engine, which will fulfill the exacting requirementshereinbefore specified, and this in a device which is simple inconstruction, reliable in operation, light in weight, low skirtexpansion and with long life.

Other objects and advantages flowing from 30 the utilizatlon of ourinvention will doubtless the wrist pin hole.

1927. Serial No. 202,623.

present themselves as the description proceeds and we would have itclearly understood that we reserve for ourselves all rights to the fullrange of equivalents, both in manner-of practicing .our method orprocess and its use, to which we may be entitled under our invention inits broadest aspect.

For a consideration of what we. believe to be novel in our invention,attention is directed to the accompanying description and claimsappended thereto.

We shall now proceed to describe our invention with reference to theaccompanying drawings, wherein we have illustrated certain preferredembodiments for the purpose of presenting a clear and comprehensivedisclosure, it being obvious that our invention is susceptible of takingother forms without departing from the scope and spirit thereof.

Fig. 1 is a plan in section, taken through D-D of Fig. 2 showing thehead metal boss extension extending down into the locking space providedin the shell section.

Fig. 2 is an elevation, in section, taken through EE of Fig. 1, showingthe inset lock section of the piston shell attached to the piston headsection.

Fig. 3 is an elevation, in section, taken through FF of Fig. 4, showingthe head 0 nilletlal extending down to lock into the piston s e l.

Fig. 4 is a plan of Fig. 3 looking toward the piston head.

Fig. 5 is an elevation showing the general arrangement of the pistonwith its shell section slotted.

Fig. 6 is an elevation showing the general arrangement of the piston,looking toward Fig. 7 is an elevation showing the piston shell with itsinset locking section.

Fig.8 is a plan of Fig. 7.

Fig. 9 is an elevation, in section, showing the piston shell with aturned in reinforcing ledge at the end of which the inset locking wallis located.

Referring now to the drawings in detail in which like characters ofreference are employed to designate similar parts throughout the severalviews, 9 indicates a piston shell constructed of some metal such as aferrous metal or other metal having like characteristics.

At 10 is shown the shell inset lock sections with lock holes 11 throughwhich the head metal flows to lock the head section and shell sectionstogether. At 12 is shown the head metal extension with wrist pin boss13. At 14 is shown the wrist pin boss rib which may be single or of anynumber found necessary for each design. At 15 is shown a ledge which mayor may not be in the piston con struction, as the individual designwarrants. At 16 is a slot to allow the shell to be flexible and is usedwhere the cylinder has not received accurate finishing. At 17 is shown apiston shell. At 22 is a reinforcing ledge adjacent the end of the shellhaving inset locking surfaces 23 with lock holes 24.

It is seen that in some instancesit may be desirable to modify thenumber or shape of the locking holes and that the wrist pin boss recessmay be modified to meet a 'diflI'erent condition of construction.

We claim:

1. A piston having a shell ofcast' iron with I a thin wall havingdiametrically opposed recesses therein extending downwardly from itsupper edge and a horizontally disposed integral inwardly projectinsurface adjacent the base of each of sai recesses and a "head of alighter metal cast on said shell to said surfaces, said dependingportions providing wrist-pin bearings.

2. A piston having a shell of cast iron formed with a thin wall havingdiametrically opposed recesses therein extending downwardly from itsupperv edge and a horizontally disposed integral inwardly projectingledge adjacent the base of each of said recesses, each of said ledgeshaving openings therein disposed on either side of the central portionthereof and a head of an aluminum alloy cast on said shell withdependent per-- tions embracing said ledges, said alloy being disposedwithin said openings, the aforesaid dependent portions being adapted toform wrist-pin bearings.

3. A bi-metallic piston having a cylindrical shell of cast iron,diametrically opposite portions of the wall being inset to form anintegral horizontally disposed inwardly projecting ledge merging into avertical upwardly directed surface, the latter surface being providedwith a wrist pin opening and a head of aluminum alloy cast upon saidshell, said head having dependent portions completely surrounding thehorizontal ledgeand the integral vertical surfaces, said dependentportions forming wrist pin bosses, and a diametrically disposedreinforcing rib integral with the inner surface of said head head havingwrist in bosses formed integral therewith and em racing the vertical andhorizontal surfaces of said inset portion of the wall, the alloy incontact with the inner and outer faces of each of said surfaces beingconnected through the a ertures therein.

HARO D A. SOULIS. WILBUR T. SOULIS.

